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The Old Aluminum vs Copper debate

I am replacing an old 13 year old condensor and coils (evaporator?) and I have had three contractors out to bid.
Two of them brought up the old alumnimum vs copper debate for the inside unit which I believe...help me here contractors...is the evaporator.
I have read online a bit and there is a lot of discussion of condensor coils...less for evaporator. The reason given by one contractor for aluminum
was corrosion and the other said the new 410 was under higher pressure and blew leaks in the aluminum. He recommended copper.
Could really use some input here.
I am looking at 3 ton unit 13 SEER.
One guy wants to install Amana. The other wants to install Lennox.
The third guy never mentioned coils, but his was the high bid for American Standard.
I don't get the feeling these guys are dishonest, they just have brand preference.

All aluminum seems to be less likely to leak being 1 metal. Today's 410 coils are designed for the pressures of 410 and they aren't going to blow. A-S Trane has their Spine Fin continuous outdoor coil that's been around for 50 years. Their indoor coils are all aluminum plate fin. Amana & Carrier have all aluminum indoor coils. Goodman has an all aluminum outdoor coil in the works. Almost everyone has an all aluminum Micro Channel outdoor coil in their line on something. Nordyne and some geo makers have it on indoor coils too. So I think that will be the way of the future. Reduces corrosion failures and is cheaper & lighter. And thieves don't want it! Never see a stripped Trane residential unit around here!!!

Yeah, you will get similar debates here. I see a lot of copper with aluminum fins (as a compromise). I heard about higher leaks with all aluminum coils where it meets the copper refrigerant lines. The other tech's can share their experiences, I just know that copper is 2X better at transferring heat than aluminum, but is 3X more expensive than aluminum. So IMO it is really down to price and if you are willing to pay more for copper.

You can call me Sam

It should be a crime to be a mechanical engineer in San Diego
Summer Design Temperature: 83 F Dry Bulb ~ 69 F Wet Bulb (California Climate Zone 7)

I just know that copper is 2X better at transferring heat than aluminum

If they were making copper tube copper fin coils, this may be a valid argument, but they are not, so it isn't.

So IMO it is really down to price and if you are willing to pay more for copper.

Copper costs more than aluminum, but aluminum tube coils cost more to manufacture, so it is probably a wash as far as final cost is concerned, or at least not much of a difference.

The problem with conventional copper tube coils is that formicary, and other corrosion, of the copper tubing has been the bane of the industry for decades.
Aluminum tubing is mostly immune to the problem, so manufacturers have been switching over to it.

isn't it the STEEL plates that the copper tubing pass through in the evaporators that cause the majority of the routine evap leaks?

I see little way to solder copper ubends with aluminum plates... and pure copper plates would likely double the price of the evap... so moving to all aluminum coils *(like many did 30 years ago...) is a wise decision.
not sure what the reasoning is for condensers being aluminum... formicary in salt air areas makes sense... but the rest of the country not so much...

The TRUE highest cost system is the system not installed properly...
The three big summer hearththrobs...
Mel Gibson
Dwane Johnson
The A/C repairman

I am replacing an old 13 year old condensor and coils (evaporator?) and I have had three contractors out to bid.
Two of them brought up the old alumnimum vs copper debate for the inside unit which I believe...help me here contractors...is the evaporator.
I have read online a bit and there is a lot of discussion of condensor coils...less for evaporator. The reason given by one contractor for aluminum
was corrosion and the other said the new 410 was under higher pressure and blew leaks in the aluminum. He recommended copper.
Could really use some input here.
I am looking at 3 ton unit 13 SEER.
One guy wants to install Amana. The other wants to install Lennox.
The third guy never mentioned coils, but his was the high bid for American Standard.
I don't get the feeling these guys are dishonest, they just have brand preference.

With options you have, the best option is the amana system. Because once the amana system is installed, the contractor or you need to register them (unless you live in CA). You will then have 10 years all parts warranty.

Lennox will only have 5 years all parts warranty with this low end 13 SEER .

Thoughts

Originally Posted by just_opinion

With options you have, the best option is the amana system. Because once the amana system is installed, the contractor or you need to register them (unless you live in CA). You will then have 10 years all parts warranty.

Lennox will only have 5 years all parts warranty with this low end 13 SEER .

Hope this angle helps.

Yeah that perspective helps a LOT. I was surprised the Lennox warranty was so much shorter considering the good rep they have. This is definitely something to think about.
But I see from the other posts that the debate rages on with no firm conclusion. I do know that the 410 is under higher pressure than the old stuff. That angle still concerns me. My old system was a TempStar and for the inexpensive system it was from the get-go it has lasted very well. HOWEVER, the one weak point was those evaporator coils which I assume were the copper.
I'll give this some thought.

FWIW, the Carrier/Bryant coils are not aluminum, they just look like they are. They're tin plated copper units. As far as warranty, almost all of the manufacturers are giving a 10-years parts warranty that is transferable to a new owner if necessary. Just register it on line if the dealer is too lazy to do it for you. And I wouldn't lose any sleep over the type of coil provided. Each salesman needs to try and get your business and will therefore use every benefit he knows to get your business.

If YOU want change, YOU have to first change.

If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!